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Genetic mechanisms of critical illness in COVID-19
by
Semple, Malcolm G.
,
Pairo-Castineira, Erola
,
Zheng, Chenqing
in
2',5'-Oligoadenylate Synthetase - genetics
,
45/22
,
45/23
2021
Host-mediated lung inflammation is present
1
, and drives mortality
2
, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development
3
. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079,
P
= 1.65 × 10
−8
) in a gene cluster that encodes antiviral restriction enzyme activators (
OAS1
,
OAS2
and
OAS3
); on chromosome 19p13.2 (rs74956615,
P
= 2.3 × 10
−8
) near the gene that encodes tyrosine kinase 2 (
TYK2
); on chromosome 19p13.3 (rs2109069,
P
= 3.98 × 10
−12
) within the gene that encodes dipeptidyl peptidase 9 (
DPP9
); and on chromosome 21q22.1 (rs2236757,
P
= 4.99 × 10
−8
) in the interferon receptor gene
IFNAR2
. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of
IFNAR2
, or high expression of
TYK2
, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte–macrophage chemotactic receptor
CCR2
is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice.
A genome-wide association study of critically ill patients with COVID-19 identifies genetic signals that relate to important host antiviral defence mechanisms and mediators of inflammatory organ damage that may be targeted by repurposing drug treatments.
Journal Article
The landscape of somatic copy-number alteration across human cancers
by
Donovan, Jerry
,
Rubin, Mark A.
,
Ebert, Benjamin L.
in
631/208/2489/68
,
631/208/737
,
692/699/67
2010
A powerful way to discover key genes with causal roles in oncogenesis is to identify genomic regions that undergo frequent alteration in human cancers. Here we present high-resolution analyses of somatic copy-number alterations (SCNAs) from 3,131 cancer specimens, belonging largely to 26 histological types. We identify 158 regions of focal SCNA that are altered at significant frequency across several cancer types, of which 122 cannot be explained by the presence of a known cancer target gene located within these regions. Several gene families are enriched among these regions of focal SCNA, including the
BCL2
family of apoptosis regulators and the NF-κΒ pathway. We show that cancer cells containing amplifications surrounding the
MCL1
and
BCL2L1
anti-apoptotic genes depend on the expression of these genes for survival. Finally, we demonstrate that a large majority of SCNAs identified in individual cancer types are present in several cancer types.
Cancer genomics refined
Two Articles in this issue add major data sets to the growing picture of the cancer genome. Bignell
et al
. analysed a large number of homozygous gene deletions in a collection of 746 publicly available cancer cell lines. Combined with information about hemizygous deletions of the same genes, the data suggest that many deletions found in cancer reflect the position of a gene at a fragile site in the genome, rather than as a recessive cancer gene whose loss confers a selective growth advantage. Beroukhim
et al
. present the largest data set to date on somatic copy-number variations across more than 3,000 specimens of human primary cancers. Many alterations are shared between multiple tumour types. Functional experiments demonstrate an oncogenic role for the apoptosis genes
MCL1
and
BCL2L1
that are associated with amplifications found in many cancers.
One way of discovering genes with key roles in cancer development is to identify genomic regions that are frequently altered in human cancers. Here, high-resolution analyses of somatic copy-number alterations (SCNAs) in numerous cancer specimens provide an overview of regions of focal SCNA that are altered at significant frequency across several cancer types. An oncogenic function is also found for the anti-apoptosis genes
MCL1
and
BCL2L1
, which reside in amplified genome regions in many cancers.
Journal Article
roadmap for natural product discovery based on large-scale genomics and metabolomics
2014
Actinobacteria encode a wealth of natural product biosynthetic gene clusters, whose systematic study is complicated by numerous repetitive motifs. By combining several metrics, we developed a method for the global classification of these gene clusters into families (GCFs) and analyzed the biosynthetic capacity of Actinobacteria in 830 genome sequences, including 344 obtained for this project. The GCF network, comprising 11,422 gene clusters grouped into 4,122 GCFs, was validated in hundreds of strains by correlating confident mass spectrometric detection of known small molecules with the presence or absence of their established biosynthetic gene clusters. The method also linked previously unassigned GCFs to known natural products, an approach that will enable de novo, bioassay-free discovery of new natural products using large data sets. Extrapolation from the 830-genome data set reveals that Actinobacteria encode hundreds of thousands of future drug leads, and the strong correlation between phylogeny and GCFs frames a roadmap to efficiently access them.
Journal Article
Degradation of complex arabinoxylans by human colonic Bacteroidetes
2021
Some Bacteroidetes and other human colonic bacteria can degrade arabinoxylans, common polysaccharides found in dietary fiber. Previous work has identified gene clusters (polysaccharide-utilization loci, PULs) for degradation of simple arabinoxylans. However, the degradation of complex arabinoxylans (containing side chains such as ferulic acid, a phenolic compound) is poorly understood. Here, we identify a PUL that encodes multiple esterases for degradation of complex arabinoxylans in
Bacteroides
species. The PUL is specifically upregulated in the presence of complex arabinoxylans. We characterize some of the esterases biochemically and structurally, and show that they release ferulic acid from complex arabinoxylans. Growth of four different colonic Bacteroidetes members, including
Bacteroides intestinalis
, on complex arabinoxylans results in accumulation of ferulic acid, a compound known to have antioxidative and immunomodulatory properties.
Human gut bacteria can degrade arabinoxylans, polysaccharides found in dietary fiber. Here, Pereira et al. identify a bacterial gene cluster encoding esterases for degradation of complex arabinoxylans. The action of these enzymes results in accumulation of ferulic acid, a phenolic compound with antioxidative and immunomodulatory properties.
Journal Article
Evolution of genes and genomes on the Drosophila phylogeny
by
Wilson, Richard K
,
Lapoint, Richard
,
Massachusetts Institute of Technology (MIT)
in
Animals
,
Biologi
,
Biology
2007
Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
Journal Article
Atlas of nonribosomal peptide and polyketide biosynthetic pathways reveals common occurrence of nonmodular enzymes
2014
Nonribosomal peptides and polyketides are a diverse group of natural products with complex chemical structures and enormous pharmaceutical potential. They are synthesized on modular nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) enzyme complexes by a conserved thiotemplate mechanism. Here, we report the widespread occurrence of NRPS and PKS genetic machinery across the three domains of life with the discovery of 3,339 gene clusters from 991 organisms, by examining a total of 2,699 genomes. These gene clusters display extraordinarily diverse organizations, and a total of 1,147 hybrid NRPS/PKS clusters were found. Surprisingly, 10% of bacterial gene clusters lacked modular organization, and instead catalytic domains were mostly encoded as separate proteins. The finding of common occurrence of nonmodular NRPS differs substantially from the current classification. Sequence analysis indicates that the evolution of NRPS machineries was driven by a combination of common descent and horizontal gene transfer. We identified related siderophore NRPS gene clusters that encoded modular and nonmodular NRPS enzymes organized in a gradient. A higher frequency of the NRPS and PKS gene clusters was detected from bacteria compared with archaea or eukarya. They commonly occurred in the phyla of Proteobacteria, Actinobacteria, Firmicutes, and Cyanobacteria in bacteria and the phylum of Ascomycota in fungi. The majority of these NRPS and PKS gene clusters have unknown end products highlighting the power of genome mining in identifying novel genetic machinery for the biosynthesis of secondary metabolites.
Journal Article
Two unequally redundant \helper\ immune receptor families mediate Arabidopsis thaliana intracellular \sensor\ immune receptor functions
by
Jones, Jonathan D. G.
,
Jubic, Lance M.
,
Castel, Baptiste
in
Airborne microorganisms
,
Angiosperms
,
Apoptosis
2020
Plant nucleotide-binding (NB) leucine-rich repeat (LRR) receptor (NLR) proteins function as intracellular immune receptors that perceive the presence of pathogen-derived virulence proteins (effectors) to induce immune responses. The 2 major types of plant NLRs that \"sense\" pathogen effectors differ in their N-terminal domains: these are Toll/interleukin-1 receptor resistance (TIR) domain-containing NLRs (TNLs) and coiled-coil (CC) domain-containing NLRs (CNLs). In many angiosperms, the RESISTANCE TO POWDERY MILDEW 8 (RPW8)-CC domain containing NLR (RNL) subclass of CNLs is encoded by 2 gene families, ACTIVATED DISEASE RESISTANCE 1 (ADR1) and N REQUIREMENT GENE 1 (NRG1), that act as \"helper\" NLRs during multiple sensor NLR-mediated immune responses. Despite their important role in sensor NLR-mediated immunity, knowledge of the specific, redundant, and synergistic functions of helper RNLs is limited. We demonstrate that the ADR1 and NRG1 families act in an unequally redundant manner in basal resistance, effector-triggered immunity (ETI) and regulation of defense gene expression. We define RNL redundancy in ETI conferred by some TNLs and in basal resistance against virulent pathogens. We demonstrate that, in Arabidopsis thaliana, the 2 RNL families contribute specific functions in ETI initiated by specific CNLs and TNLs. Time-resolved whole genome expression profiling revealed that RNLs and \"classical\" CNLs trigger similar transcriptome changes, suggesting that RNLs act like other CNLs to mediate ETI downstream of sensor NLR activation. Together, our genetic data confirm that RNLs contribute to basal resistance, are fully required for TNL signaling, and can also support defense activation during CNL-mediated ETI.
Journal Article
The emerging role of biosynthetic gene clusters in plant defense and plant interactions
2021
Interestingly, pairing of protein functionality in plant defense can also occur in the form of fusion of functional domains within a single protein; nucleotide-binding leucine-rich repeat (NLR) proteins, involved in pathogen recognition, can be fused with various protein domains that serve as baits for pathogen effectors [12]. The specialized metabolites encoded by these BGCs have diverse modes of action, for example, disrupting pathogen cell membranes [16], conferring bitterness or toxicity that deters herbivores [17,18], undergoing pathogen-induced degradation to give bioactive volatiles [19], or forming physical barriers against biotic and abiotic stress factors [20]. [...]benzoxazinoids (defense compounds produced by grasses and some eudicots) have been implicated in regulation of defense responses, flowering time, auxin metabolism, and iron uptake in maize [32]; cyanogenic glycosides serve as nitrogen storage compounds in the rubber tree [33]; and perturbation of the pathway for the oat defense compound avenacin A-1 can result in accumulation of the precursor β-amyrin with associated effects on root epidermal cell patterning [34]. Genomic factors that may contribute to the formation, regulation, and evolution of BGCs include transposable element-mediated recombination [37], chromosomal inversion [38], gene shuffling [39,40], whole genome duplications [41,42], copy number variations of genes within BGCs [43], chromatin modification [44,45], and chromosomal 3D structure [46].
Journal Article
Minimum Information about a Biosynthetic Gene cluster
by
Massachusetts Institute of Technology (MIT)
,
Geiger, Christoph
,
Düsterhus, Stephanie
in
631/114/2184
,
631/92/349
,
631/92/552
2015
A wide variety of enzymatic pathways that produce specialized metabolites in bacteria, fungi and plants are known to be encoded in biosynthetic gene clusters. Information about these clusters, pathways and metabolites is currently dispersed throughout the literature, making it difficult to exploit. To facilitate consistent and systematic deposition and retrieval of data on biosynthetic gene clusters, we propose the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard.
Journal Article
Microbial conversion of choline to trimethylamine requires a glycyl radical enzyme
by
Balskus, Emily P.
,
Craciun, Smaranda
in
Anaerobiosis - drug effects
,
Biochemistry
,
Bioinformatics
2012
Choline and trimethylamine (TMA) are small molecules that play central roles in biological processes throughout all kingdoms of life. These ubiquitous metabolites are linked through a single biochemical transformation, the conversion of choline to TMA by anaerobic microorganisms. This metabolic activity, which contributes to methanogenesis and human disease, has been known for over a century but has eluded genetic and biochemical characterization. We have identified a gene cluster responsible for anaerobic choline degradation within the genome of a sulfate-reducing bacterium and verified its function using both a genetic knockout strategy and heterologous expression in Escherichia coli . Bioinformatics and electron paramagnetic resonance (EPR) spectroscopy revealed the involvement of a C–N bond cleaving glycyl radical enzyme in TMA production, which is unprecedented chemistry for this enzyme family. Our discovery provides the predictive capabilities needed to identify choline utilization clusters in numerous bacterial genomes, underscoring the importance and prevalence of this metabolic activity within the human microbiota and the environment.
Journal Article